Field of the Invention
The present invention relates to wireless communications, and more particularly, to a communication method supporting a variable bandwidth in a wireless communication system, and a wireless device using the method.
Related Art
Long term evolution (LTE) based on 3rd generation partnership project (3GPP) technical specification (TS) release 8 is a promising next-generation mobile communication standard. Recently, LTE-advanced (LTE-A) based on 3GPP TS release 10 supporting multiple carriers is under standardization.
In a next-generation wireless communication system, it is considered to provide a service for a low cost/low specification device which primarily aims at data communication, such as reading a meter, measuring a water level, utilizing a camera, inventory reporting of a vending machine, etc.
For example, machine-type communication (MTC) is one type of data communication including one or more entities not requiring human interactions, and is also called machine to machine (M2M) communication. That is, the MTC refers to the concept of communication based on the legacy wireless communication network used by a mechanical device instead of a user equipment (UE) used by a user. The mechanical device used in the MTC is called an MTC device or an M2M device.
An MTC service requires a low transmission data amount, and not frequently transmits and receives data. Therefore, it is effective to decrease a unit cost of a device and to decrease a battery consumption according to a low data transmission rate. For example, if an operating bandwidth of an MTC device is smaller than that of the legacy mobile terminal, a radio frequency (RF)/baseband complexity of the MTC device can be significantly decreased.
Although the legacy LTE/LTE-A system also supports various bandwidths such as 20 MHz, 10 MHz, 5 MHz, etc., it cannot support wireless devices supporting a plurality of bandwidths. One base station or network system supports only one bandwidth. For example, if the base station supports a 20 MHz bandwidth, only a wireless device supporting the 20 MHz bandwidth can access the base station.
However, wireless devices supporting a narrowband such as the MTC device may be deployed within a coverage of the base station. According to the legacy mobile communication system, a device having a 5 MHz bandwidth cannot access a base station having a 20 MHz bandwidth.